Since it's mandatory to turn your headlights on when you use your wipers and I see only about 50-80% compliance with that, I'm not too convinced it's going to be followed. On the other hand, MSP patrols that stretch like they own it.
I agree with your percentages. Many folks only have their DRL's on which don't activate the tail lights. They are hard to see in the misty, foggy, snowy conditions we experience frequently on the roads.
People should learn/understand their vehicles, oops, that might mean reading their owner's manuals.